what are the differences between the nbs non-return sending units and the nnbs ones?

I'm looking at some on ebay to try and get one here to rig for the dual pumps ahead of pulling mine out to save time, etc since it is my daily driver. There are a ton that show 04-07 but nothing for 07+nnbs thought maybe they were interchangable and if they are how awesome it would be.

 

I know the clips to the bucket are different...but im the jackass that zip tied a 99 sending unit sideways on a 05 lower bucket in an 07 tank so the gauge would work